Police are reaching out to villagers in northern India to investigate the recovery of bodies buried in shallow sand graves or washed up on the banks of the Ganges, prompting speculation on social media that they are the remains of Covid-19 victims.

Officers in jeeps and boats, and using loudspeakers with microphones, asked people not to dispose of bodies in rivers.

“We are here to help you perform the last rites,” police said.

Rains on Friday exposed the cloth coverings of bodies buried in shallow sand graves on a wide, flat riverbank in Prayagraj, a city in Uttar Pradesh state.

While officials say the riverside burials have taken place for decades, the sheer numbers in the shadow of the pandemic are focusing more attention on the practice.

Navneet Sehgal, a state government spokesman, denied local media reports that more than 1,000 corpses of Covid-19 victims had been recovered from rivers in the past two weeks.

“I bet these bodies have nothing to do with Covid-19,” he said.

Mr Sehgal said some villagers did not cremate their dead as was customary, due to a Hindu tradition during some periods of religious significance, and instead disposed of them in rivers or by digging graves on riverbanks.

Ramesh Kumar Singh, a member of Bondhu Mahal Samiti, a philanthropic organisation that helps cremate bodies, said the number of deaths was very high in rural areas, and poor people had been disposing of bodies in the river because of the exorbitant cost of performing the last rites and a shortage of wood. The cost of cremation had tripled up to 15,000 rupees (£149).

An Associated Press photojournalist estimated there were at least 300 shallow riverside graves on a sand bar near near Prayagraj on Saturday.

Each grave was covered by an orange, yellow or reddish cloth and appeared to have been laid out in the same direction.

Several policemen were at the scene, but allowed a family who arrived in a small truck to bury a 75-year-old woman at the site.

KP Singh, a senior police officer, said authorities had earmarked a cremation ground on the Prayagraj riverbank for those who died of Covid-19, and police were no longer allowing any burials on the riverfront.

He said authorities had found “a small number” of bodies on the riverbanks, but did not give a figure.

But on Sunday, a 30-year-old Buddhist came to the same riverbank in Prayagraj with other family members and buried his mother, who he said had died of a heart attack.

“She was not infected with Covid-19,” Vijay Kumar told a reporter, adding that his religion allowed both cremation and burial.

Health authorities last week retrieved 71 bodies that had washed up on a Ganges riverbank in neighbouring Bihar state.

Authorities performed post-mortem examinations but said they could not confirm the cause of death due to decomposition.

A dozen corpses were also found last week buried in sand at two locations on the riverbank in Unnao district, 40km (25 miles) southwest of Lucknow, the Uttar Pradesh state capital.

District magistrate Ravindra Kumar said an investigation was under way to identify the cause of death.

India’s two big states, Uttar Pradesh and Bihar, are among the worst-hit as the virus surge sweeps the country, with devastating death tolls.

On Sunday, the country’s health ministry reported 311,170 confirmed Covid-19 cases in the past 24 hours, down from 326,098 on Saturday.

It also reported 4,077 additional deaths, taking the total fatalities to 270,284.

Both figures are almost certainly a vast undercount, experts say.

PA Media